The £150,000-a-year chief executive of the scandal-hit Tameside hospital in Manchester has quit in the wake of revelations of major failings in quality of care and patient safety.

Christine Green, who has been chief executive of Tameside NHS foundation trust for 15 years, tendered her resignation on Wednesday in the wake of mounting criticism about the hospital, including her leadership of it.

Green has been under pressure as a result of the Guardian's disclosures that two NHS reviews commissioned by Tameside had highlighted an array of problems with patient care and that local GPs in the clinical commission group wanted her out.

Her resignation follows discussions she had last week with Paul Connellan, the chairman of the hospital's board of governors. The Guardian reported on Wednesday that the board of Tameside and Glossop CCG wanted both Green and the medical director Dr Tariq Mahmood to quit to enable major improvements to be made.

Jonathan Reynolds, Andrew Gwynne and David Heyes, the three MPs whose constituents use Tameside as their main local hospital, had issued a joint statement on Wednesday urging Green to go.

"Although the majority of care delivered by the hospital's frontline staff is praised by patients, we have had serious concerns about aspects of care and governance at the hospital for some time now, which the hospital trust are well aware of. We have always stood by our previous statement that new leadership is required," the Labour trio said.

"There needs to be significant and sustained improvement across several different areas of care and management. We are confident this can be done, and in doing so local confidence in the hospital's ability to meet the needs of our community can be restored."

Detailed concerns about major problems in the care provided at Tameside, highlighted by two separate reviews by internal teams of NHS experts in best practice seen by the Guardian, bore out their own longstanding concerns, the MPs said. "We have campaigned for many years to ensure Tameside hospital delivers the level of care expected of an NHS hospital. These reports reflect our own concerns and the submission made by us to the Keogh review."

Sir Bruce Keogh's findings into standards of treatment at 14 hospitals, which are expected to be highly critical, are due to be published in the week beginning 15 July.

The MPs' intervention comes as the Care Quality Commission, which regulates NHS care, admitted that its inspectors had found problems at Tameside's A&E unit, which was heavily criticised and depicted as an overcrowded scene of chaos in the two reports.

A CQC spokesman told the Guardian it had instigated an inspection after Jacky Hayden, the postgraduate dean for Greater Manchester, passed on concerns first raised privately with her by a group of junior doctors working in several departments at Tameside.

"The deanery's concerns were raised at a meeting with NHS England and CQC inspectors and this triggered an immediate inspection of TGH's [Tameside general hospital's] accident and emergency services. Inspectors found that the hospital was not meeting standards, findings that were shared with the Keogh review team," the spokesman said.

He said he could not give details about why the A&E unit failed the inspection because the CQC's report is being finalised and he could not release details of its contents before publication. Further action is planned, however. "We plan to return to Tameside imminently to check improvements have been made and continue to work closely with NHS England and Monitor to oversee progress," he said.

Monitor, which regulates finance and governance at the growing number of semi-independent foundation trust hospitals in England, said Tameside's financial problems meant it was currently breaching the terms of its operating licence.

"Tameside NHS foundation trust has been under close scrutiny within Monitor's regulatory regime for more than two years, and is currently in breach of its licence on financial and governance grounds," said a spokesman for the regulator. "We have used our powers to secure legal undertakings that the trust will deliver cost savings to eradicate its deficit, and require the trust to develop an adequate long-term strategic plan."

But "there remains a lot of noise locally about the trust, but so far we are not aware of any evidence to justify further regulatory action", he added.

The hospital said its board had approved an action plan to tackle the problems highlighted in the two reports, which had been sent to Monitor.

Jeremy Hunt, the health secretary, said: "Substandard is completely unacceptable. Patients should not face excessive waits for treatment and junior doctors must have the support they need from consultants to provide patients with that treatment.

"Professor Sir Bruce Keogh will be publishing his report on Tameside hospital shortly. This will ensure that they have the support that they need to improve care for their patients."